The succesful retrial of the airline bomb plot suspects helps to justify the
introduction of the liquids ban on planes that has affected millions of
travellers.

The three leaders had been found guilty of conspiracy to murder last year but the Crown Prosecution Service decided it was vital to put them on trial again to prove that their targets had been transatlantic airliners.

The second jury’s decision that the trio had been intending to blow up aircraft was a vindication of the CPS’s determination to spend £10 million on a second hearing.

It was also an enormous relief for Government ministers who had been widely criticised for introducing overly tough travel restrictions in the wake of the discovery of the plot.

Lord Carlile, the Government's independent reviewer of terrorism legislation, said the pursuit of a retrial had been “crucial” to counter doubts about the security measures that were imposed at airports three years ago.

He said: “The prosecution showed great determination and judgment in pursuing a retrial. They could have said after the first trial that they had secured sufficient convictions but they were right to say the defendants had not been found guilty of the essence of what was alleged.”

Alan Johnson, the Home Secretary, said: “I am pleased that the jury has recognised that there was a plot to bomb transatlantic flights and that three people have been convicted of that plot. This case reaffirms that we face a real and serious threat from terrorism.”

The day after the suspects were arrested in August 2006 a complete ban on liquids on planes was brought in.

It is estimated that the first day of delays at airports cost airlines £175 million and extra security staff taken on by the British Airports Authority cost around £16 million per year.

However, the original trial last year ended with a jury failing to find anyone guilty on charges of intending to destroy aircraft.

It was one of the most high-profile terrorist trials of recent years and recriminations still continue over its outcome.

Security officials have privately blamed a number of factors including the premature arrest of a suspect in Pakistan and a decision to allow the jury to take a two-week holiday during deliberations.

Rules on taking liquids on to planes have since been relaxed and now state that travellers can carry 100ml containers on to an aircraft, and bottles or tubs must fit into a re-sealable bag measuring 8ins (20cm) by 8ins.

Major airlines and BAA have called for the rules to be further eased or reviewed.

Scanners are being trialled which could identify substances such as hydrogen peroxide - a chemical that can be mixed with other ingredients to produce explosives - removing the need for restrictions.